'use strict';

const containerValue = Symbol('containerValue');

class Container {
  constructor(value) {
    Object.defineProperty(this, containerValue, {
      configurable: false,
      enumerable: false,
      writable: false,
      value
    });
  }
  getValue() {
    return this[containerValue];
  }
}

// Usage

const container1 = new Container(150);
console.dir({ container1 });
console.log('container1.getValue() =', container1.getValue());

const person = { name: 'Marcus', born: 121, city: 'Roma' };
const container2 = new Container({ person });
console.dir({ container2 });
console.log('container2.getValue() =', container2.getValue());
